Novel Resonance Raman Enhancement of Local Structure around Solvated Electrons in Water

Picosecond time-resolved Raman spectra of water were measured under the resonance condition with the s → p electronic transition of the solvated electron for the first time. We found that a strong transient Raman band appears in the frequency region 30 cm -1 lower than the OH-bend band of bulk water in accordance with the formation of solvated electrons. The observed transient Raman band was assigned to the vibration of the solvating water molecules that strongly interact with the solvated electron in the first solvation shell. The mechanism of this novel resonance enhancement is discussed on the basis of the vibronic theory.